Manufacture of incandescent mantles.



-E.. L. KNOEDLER. MANUPAGTURE 0F INGANDBSGENT MANTLBS.

APPLIUATlON FILED TBB. 20 1913.

Patented Dec. 29, 1914.

2 SHEETS-SHEET 1.

INVENTOFI SNI-messes THE MORRIS PETERS Cc.. PHOTO-LITHO., WASHINGTON, D. C.

E. L. KNOEDLER. MANUFACTURB 0F INGANDBSGENT MANTLES APPLICATION FILED PBB,20.1913.

Patented Dec. 29, 1914.

2 SHEETS-SHEET 2.

Mo o como ooo o @am oop o oom@ WITN ESSES @fm THE NURRIS PETER5 CO.. PHOTO-LITHO.. wAsHlNc 10NA n. c,

TED STATES PATENT OFFICE.

ELIVIER L. KNOEDLER, OF GLOUCESTER CITY, NEW' JERSEY, ASSIGNOR TO WELSBACH LIGHT COMPANY, OF GLOUCESTER CITY, NEW JERSEY, A CORPORATION OF NEW JERSEY.

MANUFACTURE OF INCANDESCENT MANTLES.

Speccaton of Letters Patent.

g Patented Dec. 29, 1914.

Original application led February 17, 1911, Serial No. 609,194. Divided and this application filed February To all whom it may concern:

Be it known that I, ELMER L. KNonDLnR, a citizen of the United States, and resident of Gloucester City, Camden county, New Jersey, have invented a new and useful Improvement in the Manufacture of Incandescent Mantles, of which the following is a full, clear, and exact description, reference being had to the accompanying `drawings, forming part of this specification, 1n which- Figure l is a vertical section showing one form of muffle mold and burner arranged for carrying out my invention, with an inverted mantle in place; Fig. 2 is a side elevation of the maille mold; Fig. 3 is a bottom plan view of the same; and Fig. d is a cross-section on the line IV-IV of Fig. 2. Figs. 5, 6 and 7 are vertical sections illustrating modiiied forms of the muffle.

My invention relates to the shaping and hardening of incandescent gas mantles. Heretofore this work has been done in the open air, the mantle not being inclosed nor effectually protected. In the best practice one mantle is handled at a time, the shape and size of the mantle being determined partly by the fabric used, and partly by the force of the Bunsen flame directed into it. In many cases the burning out and preliminary shaping were carried out by one burner, theY mantle being then removed to the hardening station where a sharper flame of higher temperature was used, the vfirst flame being soft and not capable of giving a hardening action. In. case of inverted mantles the hardening operation was carried out by the use of two burners one above and the other below the mantle. The shaping of the mantle was effected by the adjustment, or by hand manipulation of the -hardening flames, and consequently the mantles have varied seriously in size and shape and could not be made to a pattern. This hardening operation has demanded a high degree of skill and care 0n the part of the operator, and even with a skilful operator many of the mantles will bulge or warp and deform during the hardening operation. This gives a considerable percentage of loss, and causes a proportionate increase in cost Serial No. 749,655.

of manufacture, as the final shape is given to the mantle in this hardening operation. In addition to loss from defective mantles, a large amount of gas was consumed, and the hardening operation for each mantle occupied a considerable period of time, with skilled and expensive labor. Moreover, in order to produce even a reasonable number of first-class mantles it was necessary to use extreme care in many of the preliminary operations, such as in cutting the blanks from the tubular length of fabric, in mounting the blank on the ring, in closing the point of the mantle, in modeling and shaping out the creases and plaits, as well as in the i'inal steps of burning out and hardening. In the case of upright mantles, a number of steps also required great care previous to the burning and hardening. The burning and hardening operation also required separate and individual treatment of each mantle, so that mantles could not be burned and hardened in sets, if a first-class uniform product was to be obtained. Also the hardening room must be carefully protected against drafts, thus giving an uncomfortable atmosphere therein.

It has been proposed to model or shape an upright mantle by blowing it out against the wall of a surrounding frustum of a cone during burning by the use of an interior flame under pressure, the cone having a suiiicient number and size of orifices to allow escape of the products of combustion so that the mantle will contact with the material of the cone during burning and preliminary shaping of the mantle. But the mantle was to be removed and hardened under higher heat in the ordinary manner, during which time it will become Warped or otherwise distorted, thus preventing making the mantles to a pattern. This proposed method was impracticable, because the flame within the mantle and cone was a soft flame used for preliminary shaping purposes, and incapable of hardening; and, second, because the oXid material of the mantle is forced against and into contact with the walls of the cone, which, on account of radiation, cannot reach a hardening temperature. In this case, as only the preliminary modeling is carried out within the cone, and

the mantle is then removed and hardened without any surrounding mold, much of the product becomes deformed and cannot be made to a pattern; and, furthermore, I have found that it is imposible to harden the oxid when brought into Contact with the walls of such a cone, even if a burner affording high heat were provided. It has also been proposed to harden the portion of the inverted mantle immediately adjacent to the supporting ring, by inserting the mantle within a flame-deflecting cylinder so that the flame and gases are deflected through that portion of the mantle adjacent to the ring which is just above and outside of the cylinder and which it is desired to harden. Here there was no attempt at shaping the mantle and giving it a pattern or fixed contour or shape.

I have discovered that I can shape or pattern a mantle and harden it within a surrounding perforated shaping or muflle mold, provided the perforations are so proportioned and arranged and the mold so shaped, that while a restricted escape of the products of combustion is allowed, yet a cushion of hot gases is maintained between the mantle and the shaping mold of a substantially uniform thickness or depth between the mantle and the wall of the mold; at least, as to those portions of the mantle which it is desired to make to a pattern or predetermined shape. In obtaining this desirable result, not only is the shape of the mold important, but the size, number and arrangement of the gas outlet holes must be carefully worked out so that the intermediate cushion of hot gases will give the desired shape to the mantle while holding it away from actual contact with the wall of the muflle mold. I have found that actual contact between any part of the mantle and the mold must be prevented, since any such portion will not be hardened during the operation, as desired.

I will now describe my invention specifically as applied to one form of inverted mantle, it being understood, however, that it may be applied to mantles generally, including upright mantles, by suitably shaping the mold and its escape outlets for each particular case.

In carrying out my operation, the shaping and hardening are effected in the same shaping muflle mold by a rapid, cheap and simple operation which does not require skilled labor. In the case of an inverted mantle, where it is desired to shape not only the sides but the dome-shaped end thereof, I preferably provide a mold such as shown in Figs. 2, 3 and :t of my drawings. This mold may be either made of a refractory metal such as platinum, or other metal, or of refractory ceramic material, or other composition which will withstand the heat.

In the form shown, there are 261- holes in the sides of the mold, each having a diameter of .059'inch- There are 94 holes in the domeshaped end or base of the mold, having a diameter of .OSG of an inch. 'Ihe drawings filed herewith are full size, the holes being shown as accurately as possible to a scale and with the space and arrangement as shown. The total area of holes is in this form approximately 24 per cent. of the total area of the mold. This being distributed as about 13 per cent. in the walls and l1 per cent. in the bottom or dome. The arrangement, number and size of these holes will depend somewhat upon the pressure and type of burner used, and with the moldshown I have used with good results an air pressure of 2.1 pounds and a gas pressure of 3 inches of water with a burner having an orifice of 19/32 of an inch. With this arrangement, I have been able to eifectually harden mantles to a pattern within the mold 2 by means of the burner 3, which does not enter the mold or mantle, but is spaced slightly apart from it, as shown in Fig. l. The open mouth portion 4 of the mold is preferably fiared outwardly and provided with a centering shoulder 5 having interior diameter corresponding tothe outer diameter of the legs 6 of the refractory ring 7 to which the mantle is secured. The mixer tube 3 of the burner preferably has an axis registering with the longitudinal axis of the mantle and mold, and projects a flame giving a high degree of heat renheit, used in hardening.

The dome-shaped portion 8 of the mold is preferably of the shape desired to be given to the dome-shaped end of the mantle. In using the mold, `the mantle 9 carried by its ring is inserted in the mold, the mold preferably depending vertically as shown in Fig. 1. The mold and burner are then brought into a proper registering and concentric position, and the shaping and hardening carried out. In the ordinary hardening operation, the flame must he carefully applied so as not to blow a hole through the fragile oXid of the mantle; but by the use of my invention the hardening flame may be applied more abruptly and suddenly and without using care and skill in its manipulation. rIhe mantle will in this operation be blown out toward the mold, but will be held away from that wall by the intermediate cushion of hot gases, which are baffled to some eX- tent by the walls and the lack of free exit. T he mantle is thus held out of actual contact with the walls, so that the hardening temperature is quickly reached, the mantle being surrounded with hot gases on both sides. This small cushion of gases is held as nearly as possible of the same thickness or depth at all points of the mantle, so that the mantle will take substantially the shape 1200 or 1300 degrees Fahr of the surrounding inutile mold. This is carried out by properly proportioning the size and arrangement of the holes. The gases must not, of course, be baffled too much, as in such case they will force part of the mantle inwardly and destroy its proper uniform shape. After the shaping and hardening operations, which are simultaneous in my case, and which may be carried out in about one minute, the mantle is removed from the mold, another mantle inserted, and the operation repeated.

The advantages resulting from my invention are numerous and important. The mantles thus produced are substantially of the same form or pattern, one being like another. At the same cross-section the series of mantles produced will be of substantially the same cross-sectional area and shape. This is a result which has heretofore been impossible of attainment, for the reasons before stated. This uniformity is not only of great value in making the man tles more attractive in appearance, but saves much time and expense in adjusting the burner each time a new mantle is put on. 1n cases Where gas companies take contracts for maintenance of incandescent lamps, readjustment of each burner must ordinarily be had with each replacing of the mantles. With the use of my improved pattern mantles, this is unnecessary and the mantles are also more uniform in candle power and less liable to carbonize. rihe mantle is also found to be stronger and to conform substantially to speciiied requirements for size, shape and candle power.

The considerable amount of loss-10 to 30 per cent-which has heretofore occurred in manufacturing` inverted mantles, owing to those that must go into seconds or be destroyed, is greatly reduced, and almost done away with. This, therefore, reduces the cost of mantle-making from l0 to 20 per cent. Moreover, the cost of making of the preliminary operations, such as cutting the web, mounting on the ring, closing up the point, and modeling or stretching the point, is greatly reduced, all since the care and time heretofore required are not necessary. This isbecause the use of the shaping mold gives a uniform product, even where inaccuracies occur' in the previous steps. In other words, the mold will correct an imperfect blank. Also, it has heretofore been necessary in the hardening operation to expose the mantle to the hot flames for 23,- to 3 minutes to give it permanently hardened shape, this operation also requiring great care and skill. By the use of my method, this time is reduced to about a minute, thus effecting a large saving in gas and also a great increase in output and a lower labor cost.

The great care heretofore necessary 1n selecting and packing the mantles is simplified and cheapened, since almost without eX- ception the mantles produced by my method are first-class in quality and alike in appearance. The mantle is also permanently fixed to the ring during the hardening operation. The muftle action not only gives it a quicker hardening but a bettter hardening, as mantles thus treated are found to be harder and to retain their shape better than mantles made by other methods. The dome is also better shaped and the creases arc less prominent. The mufiie action gives a high temperature, and a superior mantle. rlhis is of especial importance in the case of light-weight high-candle power mantles, the making of which under present methods is a serious and difficult problem.

rlhe use of my method enables almost any kind of ay shape to be made. For instance, in an inverted mantle almost any shape may be had, from a sharp cone shape to a blunt short dome shape. Also, a mantle of square, tlnee-cornered, or other cross-section, may be made, which has heretofore been impossible. Owing to the jacket of hot gases between the mantle and the mold, the hardened mantles may be easily removed without danger of breakage. This is also helped by the contraction of the oxid mantle during cooling, this taking place as soon as the heat is reduced or withdrawn.

The difficulty of proper ventilation of a hardening room is done away with when this method is used. Heretofore, such rooms have been very hot and uncomfortable, since a very slight draft while the mantle is exposed to the flames will'cause it to become crooked. The mantle is plastic when heated to the high hardening temperature, and when exposed in the air as heretofore, any draft of air will distort it. My invention overcomes this difficulty, because the mantles are shaped within the muiiie mold and protected from drafts or other disturbances. rThis enables hardening rooms to be properly ventilated. I have also found that by proper burner arrangements, I can keep the burner beyond the end of the mold and beyond the mantle ring, thus avoiding possible chipping and breakage of the ring.

Another important feature of advantage lies in the fact that a series of burners may be employed to harden a series of mantles within their molds by the use of a single control valve for the gas and one control valve for the air. Heretofore, a gas valve and an air valve were necessary for each separate mantle; where under my invention a series of them may be hardened simultaneously by a single control for the set. By sliding a frame containing a series of the molds under a series of properly arranged hardening burners, the whole series of man tles may be hardened at one time' within their muffle molds and the frame then removed to allow insertion of the new frame, thus giving great rapidity and cheapness of operation.

It will be seen that the essential feature of my invention consists in hardening the mantle and simultaneously shaping it against the action of a thin cushion of hot gases between the article and the walls of the shaping cavity, sufficient escape for the gases being provided to give a restricted outlet and prevent such a back pressure as would dis tort the mantle, while, at the same time, maintaining the shallow cushion. In order to effect this, the escape of the gases must be provided for, but such escape is so controlled as to maintain the cushion while preventing injurious back pressures which would distort the mantle. In obtaining this result, I preferably perforate the side walls of the shaping cavity or inutile. I also preferably employ a muffle having a perforated closed end, this end portion of muflie also preferably conforming approximately to the shape of the closed end of the finished mantle. In the hardening of inverted mantles, however, I may use a muliie, with an open end, but in all cases, the mule walls must lne-sufficiently close to the mantle being hardened to prevent substantial side movement thereof and thus give sidewise distortion and misshaping of the mantle while maintaining the shallow gas cushion between the mantle and muflie walls.

|Ihe side walls of the muflle must be sufiiciently close to the mantle walls during hardening to prevent distortion of the mantle as a whole to one side or improper bulging laterally. If the wall of the mufiie is too far away from the mantle, the mantle will distort sidewise and give a misshapen product. It is therefore important to my invention that a thin cushion of hot gases be main tained around the mantle between it and the concentric adjacent wall of the muflie, as this prevents side distortion and gives pat* terned mantles.

In F ig. 5, I show one form of open bottom mantle, this being shown as a cylindrical tube having a downward extension 11 with perforations 12 in the upper portion of the muffle. Another modification of my invention is that shown in F ig. 6, in which the muffie 13 has an imperforate lower end wall 14, but the latter is considerably below the end of the mantle, and the perforations in the side walls are also shown as extending considerably below the end of the mantle. In these modifications, as well as in the form first described, the cushion of hot gases is maintained so as to prevent any actual con tact between the mantle and the walls of the muffle.

Fig. 7 shows another modification in which a second muffle 15 is placed around the muffle shown in Figs. l and 2 so as to have a confining effect upon the hot gases escaping through the perforated wall of the inner muffle. This gives a higher temperature and increased hardening effect.

It will be understood that the sizes and arrangement of perforations herein described may be departed from provided the cushion of hot gases is maintained of the character described; that the shape of the muflie may be changed, it may have both ends open, and that various other changes may be made without departing from the invention, since I consider myself to be the first'to successfully harden and shape a mantle within a shaping cavity or muiiie.

1. In the manufacture of incandescent mantles, the steps consisting of inserting an unhardened mantle concentrically within a muffle whose side walls are sufficiently close to the muffie being hardened to prevent substantial side distortion thereof, directing a hardening flame into the interior of said mantle, maintaining a thin cushion of hot gases between the sides of the mantle and the side walls of the muffle, and simultaneously hardening and shaping the mantle against this enveloping gas cushion; substantially as described.

2. In the manufacture of incandescent mantles, the steps consisting in inserting an unhardened mantle within a mufiie in a position where that portion of the mantle adjacent to the supporting ring is within the muffie body, directing a hardening flame into the interior of said mantle, and maintaining a thin cushion of hot gases between the sides of the article and the sides of the muffle and simultaneously hardening and shaping the mantle out of Contact with the side walls and against the gas cushion maintained between the mantle and the side walls; substantially as described.

3. The method of hardening and shaping that portion of a mantle adjacent to the supporting ring thereof, consisting in inserting said portion within a muffle, directing a hardening flame into the interior of the mantle and maintaining a thin cushion of hot gases between the sides of said portion of the mantle and the side walls of the muffle, and hardening and shaping said portion out of contact with the side walls and against the thin gas cushion maintained between said mantle portion and the concentric side wall of the muflle, substantially as described.

L In the manufacture of incandescent mantles, the steps consisting of inserting an unhardened mantle within a muffle having perforated side walls, directing a hardening fiame into the interior of said mantle, allowing a restricted lateral How of the hot gases through said perforated side walls, while maintaining a cushion of said gases between the sides of the article and said perforated side walls, and simultaneously hardening and shaping the mantle out of Contact with the side walls and against the gas cushion maintained between the mantle and the perforated side walls, substantially as described.

5.1n the manufacture of incandescent mantles, the steps consisting of inserting an unhardened mantle within a muffle having perforated side walls and an interior shape conforming approximately to the shape of the body portion of the finished mantle, directing a hardening flame into the interior of said mantle, allowing a restricted lateral flow of the hot gases through said perforated side walls, while maintaining a cushion of said gases between the sides of the article and said perforated side walls, and simultaneously hardening and shaping the mantle out of contact with the side walls and against the gas cushion maintained between the mantle and the perforated side walls, substantially as described.

6.1n the manufacture of incandescent mantles, the steps consisting 'of inserting an unhardened mantle within a muffle having one end closed and provided with perforations in its sides and closed end, directing a hardening flame into the interior of said mantle, allowing 'a restricted lateral flow of the hot gases through said perforated side walls, while maintaining a cushion of said gases between the sides of the article and said perforated side walls, and simultaneously hardening and shaping the man tle out of Contact with the side walls and against the gas cushion maintained between the mantle and the perforated side walls. substantially as described.

7.1n the manufacture of incandescent mantles, the steps consisting of inserting an unhardened mantle within a muifle having perforated side walls, directing a hardening fiame into the interior of said mantle, allowing a restricted lateral flow of the hot gases through said perforated side walls, centering the mantle ring relatively to the Inutile, while maintaining a cushion of said gases between the sides of the article and said perforated side walls, and simultaneously hardening and shaping the mantle out of contact with the side walls and against the gas cushion maintained between the mantle and the perforated side walls. substantially as described.

8.1n the manufacture of incandescent mantles. the steps consisting of inserting an unhardened mantle within a partially confined atmosphere of hot gases, directing a hardening flame into the interior of said mantle, maintaining a cushion of hot gases around the mantle, hardening the mantle against the cushion of said hot gases, and

allowing'a regulated escape of the gases sufficient to prevent back pressure and distortion of the mantle, substantially as described.

9. A muffle for shaping and hardening incandescent mantles having perforations in those portions of its side walls which inclose the mantle, said perforations being ar ranged to allow restricted escape of the hot gases, while maintaining a hot gas cushion between said perforated side walls and the sidewalls of the mantle being hardened, substantially as described.

10. A muffle for hardening and shaping incandescent mantles having perforations in those parts of its side walls which inclose the mantle being hardened, said perforations being arranged to allow restricted escape of the hot gases, while maintaining a hot gas cushion between said perforated side walls and the side walls of the mantle, said inutile having openings at both ends, substantially as described.

11. A muffle for hardening and shaping incandescent mantles having perforations in those parts of its side walls which inclose the mantle being hardened, said perforations being arranged to allow restricted escape of the hot gases, while maintaining and shaping the hot gas cushion between said perforated side walls and the side walls of the mantle, in combination with means for centering the mantle in said muifle, substantially as described.

12. As a new article of manufacture, a mantle-shaping and hardening mold having perforations through the walls thereof both around and bevond its mantle-containing cavity; substantially as described.

13. As a new article of manufacture, a perforated mantle-shaping and hardening mold for inverted incandescent mantles, said mold having its upper portion provided with means for the supporting and centering engagement therewith of a mantle-supporting ring; substantially as described.

14. As a new article of manufacture, a shaping and hardening mold for incandescent mantles, having a mold cavity conforming generally to the shape of a finished mantle, but of larger cubical area, said mold having an end wall and both the end and side walls being perforated; substantially as described.

15. As a new article of manufacture, a shaping and hardening m'old for incandescent mantles, having a mold cavity conforming generally to the shape of a finished mantle, but of larger cubical area, said mold having an end wall and both the end and side walls being perforated, together with means whereby the mantle may be accurately centered in said mold; substantially as described.

16. A. inutile for hardening and shaping incandescent mantles having openings at both ends, in combination with a burner arranged to direct a hardening fiame into the interior of the mantle, and means for supporting the mantle within said muiile in such a position that restricted outlets for the gases are afforded, said outlets being arranged to maintain a hot gas cushion between the side walls of the muilie and the side walls of the mantle being hardened, while preventing injurious back pressure, substantially as described.

17. A muii'le for hardening and shaping incandescent mantles having openings at both ends, in combination with a burner arranged to direct a hardening flame into the interior of the mantle, and means for supporting and centering the mantle within said muiiie in such a position that restricted outlets for the gases are afforded, said outlets being arranged to maintain a hot gas cushion between the side walls of the muflie and the side walls of the mantle being hardened, while preventing injurious back pressure, substantially as described.

18. The combination with a mantle shaping and hardening mold having perforated side Walls, of a support for the mantle-carrying ring, and a hardening burner whose end is wholly outside of and beyond the mantle-supporting ring during the hardening operation; substantially as described.

19. As a new article of manufacture, a mantle shaping and hardening muftle having a closed end, said end, together with the side walls of the muiie, being formed of perforated material, the perforations in the closed end being larger than those in the side walls; substantially as described.

20. As a new article of manufacture, a mantle-shaping and hardening mulile of such a diameter that its walls are sufficiently close-to the mantle being hardened to pre` vent sidewise distortion thereof, said muflie having a hot gas outlet, and said Walls and outlet being arranged to maintain a thin hot gas cushion between the sides of the mantle and said walls and against which cushion the .mantle is hardened and shaped, said cushion holding the side walls of the mantle out of contact with the side walls of the Inutile at all points; substantially as described.

In testimony whereof, I have hereunto set my hand.

ELMER L. KNOEDLER.

Witnesses: p

J. H. JOHNSON, R. B. VAsmNGToN.

Copies of this patent may be obtained for five cents each. by addressing the Commissioner o! Patents,

Washington, D. C. 

